Dual jack assembly for marine loading arms

ABSTRACT

A dual jack assembly for supporting the outboard end of a marine loading arm on the deck of a marine tanker to which it is connected during transfer of fluid between the tanker and a reservoir facility. The jack assembly comprises a pair of hydraulic motor-operated jacks secured to opposite ends of a saddle structure that serves the double function of attaching the assembly to the arm and transferring the arm&#39;&#39;s moment load to the jacks. The jacks are oriented vertically, and each contains a helically threaded screw that is extended or retracted from a tubular housing in response to operation of the motor to which it is connected. The jacks are individually adjustable to compensate for different distances between the saddle structure and the tanker&#39;&#39;s deck, and the lower end of each jack terminates in a ball joint that carries a foot-like base which adapts to the slope of the deck or other structure on which the jack is based.

United States Patent [191 Gibbons [451 Mar. 26, 1974 DUAL JACK ASSEMBLYFOR MARINE LOADING ARMS Harold M. Gibbons, Long Beach, Calif.

[73] Assignee: FMC Corporation, San Jose, Calif.

[22] Filed: Apr. 3, 1972 [21] Appl. No.: 240,612

[75] Inventor:

[52] US. Cl 137/615, 248/49, 254/101, 254/102 [51] Int. Cl. F161 3/08[58] Field of Search 248/49, 59, 157, 188.4; 254/98, 102, 101, 92;137/615, 276; 415/66, 67

[56] References Cited UNITED STATES PATENTS 2,674,438 4/1954 Dalton254/92 X 2,472,654 6/1949 Engelke 248/49 3,554,475 l/l97l Benno 248/59 X2,739,788 3/1956 Weaver 254/102 3,472,474 10/1969 Fountain et 31....248/65 X 2,131,296 9/1938 Petsche et al 254/102 Primary ExaminerRoy D.Frazier Assistant Examiner-Rodney H. Bonck Attorney, Agent, or FirmW. W.Ritt, Jr.; C. E. Tripp 5 7] ABSTRACT A dual jack assembly for supportingthe outboard end of a marine loading arm on the deck of a marine tankerto which it is connected during transfer of fluid between the tanker anda reservoir facility. The jack assembly comprises a pair of hydraulicmotoroperated jacks secured to opposite ends of a saddle structure thatserves the double function of attaching the assembly to the arm andtransferring the arm's moment load to the jacks. The jacks are orientedvertically, and each contains a helically threaded screw that isextended or retracted from a tubular housing in response to operation ofthe motor to which it is connected. The jacks are individuallyadjustable to compensate for different distances between the saddlestructure and the tankers deck, and the lower end of each jackterminates in a ball joint that carries a footlike base which adapts tothe slope of the deck or other structure on which the jack is based.

10 Claims, 11 Drawing Figures PATENIEDMARZS 1914 3799197 sum 1 or sPATENTEOuanas I974 3799.197

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PATENTEDIARZB I974 sum 3 or 5 TIB' q DUAL JACK ASSEMBLY FOR MARINELOADING ARMS BACKGROUND OF THE INVENTION During transfer of petroleum orother fluid cargo between a reservoir facility and a marine tanker witha marine loading arm, such as that described in Bily US. Pat. No3,382,893, issued May 14, 1968, various conditions arise which causeexcessive moment loads to be imposed on the tankers manifold flange towhich the arm is connected. The arms required to carry out this taskwith the giant modern supertankers are huge in size, having reaches upto 100 feet, diameters as great as 24 inches, and total weights of 30 ormore tons. The moment loads imposed by the outboard end of these armsupon the tankers manifold can exceed the manifolds strength, such aswhen cast iron manifolds are involved, and this can result in failure ofthe manifold and potentially great spillage of the petroleum or otherliquid being transferred. Although some manifolds are constructed ofhigh strength steel, others of cast iron and other relatively lowstrength metals are still quite common, so that the problem ofpreventing manifold failure and cargo spillage is prevalent throughoutthe tanker industry.

Attempts to overcome this problem by counterbalancing the loading armhave enjoyed some success, but these couhterbalancing systems are hugein size and weight, and also are quite expensive. Furthermore, unlessthe loading arm can be counterbalanced while it is full of fluid, theweight of just the fluid can be sufficient to cause failure of themanifold. On the other hand, if the loading arm is counterbalanced whenin a full condition, it is so out of balance when empty that it canconstitute a real hazard to maneuvering it in and out of its stowedposition.

Providing adjustable counterweights that can be hydraulicallyrepositioned to change their counterbalancing moment while the arm isconnected to the tanker manifold, thereby balancing the arm in both theempty and the full condition, is a solution to the problem. However, theequipment required to implement this solution is rather elaborate andexpensive, and it can cause additional problems if for any reason itfails to function properly.

Accordingly, one object of the present invention is to provide anapparatus for supporting the outboard end of a marine loading arm on thedeck or other sufficiently strong structure of a marine tanker while thearm is engaged with the tankers manifold flange.

Another object of the present invention is to provide a jack-typesupport for the outboard end of a marine loading arm that can beadjusted to compensate for unequal distances between the tankersmanifold flange and the deck beneath it.

Still another object of the present invention is to provide a dual jackassembly for transferring the downward movement existing at the outboardend of a marine loading arm to the deck or other adequate supportstructure of a marine tanker instead of to the tankers manifold to whichthe arm is coupled.

Yet another object of the present invention is to provide ahydraulically powered, dual jack assembly for the outboard end of amarine loading arm, the assembly having a hydraulic system facilitatingindividual manipulation of the two jacks.

A further object of the present invention is to provide a dual jackassembly with feet or base members that automatically compensate foruneven deck or other surfaces on which the assembly is standing.

SUMMARY OF THE INVENTION The present invention comprises a dual jackassembly for mounting on the outboard end of a marine fluid loading arm,the assembly functioning to transfer the downward moment existing atthat end of the arm to a tankers deck or other sufficiently strongfoundation instead of to the tankers manifold to which the arm iscoupled. The assembly comprises a pair of hydraulically powered screwjacks positioned vertically at opposite ends of a saddle structure thatfunctions to support the arm and transfer its moment load to the jacks,and also to removably secure the assembly in rotatable manner about thearm s outer surface. Each jack is provided with its own hydraulic motorthat rotates a helically threaded screw for extending and retracting thejacks leg with respect to the tubular housing in which the leg isslidably fitted. The bottom end of each leg carries a foot attached toit by a ball joint, enabling the foot to adjust to the slope of thetankers deck or other surface on which it rests. The two motors areinterconnected by a hydraulic circuit that facilitates their operationseparately and in unison, thereby assuring that both jack legs can beextended into full contact with the deck, etc., after the loading arm iscoupled to the tankers manifold.

- BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammaticrepresentation in perspective of a double counterbalanced marine loadingarm located on a wharf. with a dual jack assembly according to thepresent invention attached to the outboard end of the arm just behindits terminal flange.

FIG. 2 is a view like FIG. 1, illustrating the marine loading armconnected to a manifold flange of a marine petroleum tanker alongsidethe wharf.

FIG. 3 is a front elevation of the dual jack assembly of the presentinvention, on an enlarged scale, with the loading anns terminal flangeremoved and the jack assembly in retracted condition.

FIG. 4 is a longitudinal section of one of the jacks of the dual jackassembly of FIG. 3, on an enlarged scale.

FIG. 5 is an enlarged view taken along the line 55 of FIG. 4.

FIG. 6 is an enlarged view taken along the line 6-6 of FIG. 4.

FIG. 7 is an enlarged view taken along the line 7-7 of FIG. 4.

FIG. 8 is a fragmentary view of the upper portion of FIG. 4, showing thejack in partially extended condition.

FIG. 9 is a fragmentary view in perspective of the upper end of thejacks drive nut and the upper stop member on the jacks screw as theyappear when the jack is in fully retracted condition.

FIG; 10 is a fragmentary view in perspective of the jacks drive nut andthe lower stop member on the jacks screw as they appear when the jack isin fully extended condition.

FIG. 1 1 is a diagrammatic representation of one type of hydraulicsystem that can be employed for operating the dual jack assembly of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In reference first to FIGS. 1and 2, the preferred embodiment of the present invention comprises adual jack assembly designed for attachment to the outboard end of amarine loading arm 22 that is shown mounted on a wharf 24 fortransferring fluid between a marine tanker 26 and a reservoir facility(not shown). The illustrated marine loading arm 22 comprises an innerfluid-conducting boom section 22a pivotally mounted on a riser 22r formovement with respect thereto about a horizontal axis A and a verticalaxis B, an outer fluid-conducting boom section 22b pivotally connectedto the inner boom section 220 for movement with respect thereto aboutanother horizontal axis C, and a fluid-conducting coupling assembly 22cat the outer end of the outer boom section 22b for connecting theloading arm in fluid-tight manner. to the manifold flange 28 of thetanker 26.

The loading arm 22 is of the double counterbalanced type, including aprimary counterweight 30 mounted on a rearward strut-like extension ofthe inner boom section 22a for counterbalancing the entire arm about thehorizontal axis A at the riser 22r, and a counterweight 32 pivotallymounted about the risers horizontal axis A for counterbalancing theouter boom section 22b and its coupling assembly 22c about thehorizontal axis C when the outer boom section is not in a verticalattitude. Such type of loading arm and its counterbalancing system aredescribed at length in Bily U.S. Pat. No. 3,340,907, and since thedetails thereof are not critical to the present invention a furtherdescription of its structure is deemed not necessary for a clear andcomplete understanding of the present invention.

Referring now to FIGS. 3 and 4, the dual jack assembly 20 comprises apair of individual jacks 34,36 fixed in vertical orientation to oppositeends of a support structure 38. This support 38 includes a transverselbeam element 40, and an arcuate saddle element 42 secured to the l-beamby upright struts 43. The support 38 functions not only to transfer thedownward move ment load of the loading arm to the jacks 34,36, andthrough them to the tankers deck on which they stand, but also tocooperate with an arcuate strap member 44 to removably attach the entirejack assembly 20 to the coupling assembly 226.

Solely for illustrative purposes, the dual jack assembly 20 is shownpositioned on the coupling 22c just behind its terminal flange 46 (FIGS.1 and 2), with the saddle 42 and the strap 44 fitting in a groove 50(FIG. 3) in the couplings outer surface. It should be understood,however, that if desired the jack assembly 20 also can be attached tothe couplings swivel joint 56 (FIG. 3) that is located behind thecouplings terminal flange 46.

A pair of bolts 52 (FIG. 3) provide a means for securing the strap 44 tocars 54 fixed to the outer surfaces of the jacks 34,36, so that the jackassembly 20 can be quickly and easily removed from the loading armshould repair or replacement become necessary. Preferably the strap 44is secured just tight enough to be snug, but loose enough to allow thejack assembly 20 to rotate relative to the coupling 22c, should that forany reason be necessary. It should be noted that the vertical supportprovided by the dual jack assembly 20 is centrally positioned beneaththe coupling 220, so that no lateral or twisting moment is imparted tothe arm as would occur if but a single jack were mounted on one side ofthe coupling.

As seen best in FIG. 4, each jack includes an outer tubular housing 60,a tubular leg 62 slidably received in the housing 60, ahelically-threaded screw 64 extending downwardly inside the leg 62, ahydraulic powered motor 66 (67 for jack 36), and a foot 68 connected tothe leg 62 by a ball joint 70. The housing 60 is welded or otherwisefixed to the transverse l-beam 40, and the ears 54 to which the strap 44is bolted are welded or otherwise fixed to the housing at a suitableheight above the I-beam.

Each of the hydraulic motors 66,67 is secured to a bearing housing 72 bymeans of cap screws 74, and the bearing housing 72 is in turn secured bycap screws 76 to an annular flange 78 welded or otherwise fixed to theupper end of the jacks housing 60. Each hydraulic motor also has a shaft80 (FIG. 4) that is non-rotatably connected, i.e., splined, keyed, etc.,to a screw shaft 82 that is welded or otherwise fixed to the upper endof the helically-threaded screw 64. A radial bearing 84 and a thrustbearing 86 are provided between the shaft 82 and the bearing housing 72.Accordingly, when the hydraulic motors are operated, each shaft 80causes the shaft 82 to which it is connected to rotate, thereby alsorotating the related screw 64. However, during this rotation the housing60 remains stationary.

The leg 62 is provided with a longitudinal groove 62a (FIG. 4) along itsouter surface that accepts an antirotation guide member 90 that extendsinwardly from, and is bolted or otherwise secured to, the lower end ofthe housing 60. Thus the housing 60, which remains stationary withrespect to the coupling assembly 22c, prevents the leg 62 from rotatingwhen the hydraulic motor is operating.

A drive nut 92 is welded or otherwise flxed to the upper end of the leg62, and is provided with inner helical threads that mesh with the outerhelical threads on the screw 64. Since the leg 62 is incapable ofrotation, the drive nut 92 likewise cannot rotate. Therefore, as thescrew 64 rotates the drive nut 92 is caused to move along the screw 64,carrying with it the leg 62.

Since the threads on the screw 64 and the drive nut 92 are left handed,when the screw is rotated clockwise as viewed from above, i.e., in thedirection of the arrow in FIG. 9, it causes the drive nut to movedownwardly, thereby extending the leg 62 and the foot 68 from thehousing 60. In corresponding manner, when the motor is reversed torotate the screw 64 counterclockwise, i.e., in the direction of thearrow in FIG. 10, the drive nut is caused to move upwardly in thehousing 60, thereby retracting the leg 62 and the foot 68.

A stop (FIGS. 5 and 9), bolted or otherwise secured to the shaft 82,cooperates with an axially extending stop element 102 on the top of thedrive nut 92 to prevent further upward movement of the nut with respectto the screw 64 when the jacks leg 62 is fully retracted. Similarly, thelower end of the screw 64 (FIGS. 6 and 10) is provided with a radiallyextending stop element 104 that cooperates with a stop 106 on the lowerend of the drive nut 92 to prevent further downward movement of the nutwith respect to the screw when the jacks leg 62 is in its fully extendedposition. Accordingly, it is seen that maximum movement of the drive nut92 along the screw 64 is restricted to the limits established by thestops 100,106 and the cooperating stop elements 102,104, therebypreventing over-extension or retraction of the leg 62 with respect tothe housing 60. It should, however, be understood that downward movementof the nut 92, and therefore also the leg 62, will cease when the foot68 comes to rest on the tankers deck or other supporting surface, eventhough the nut has not reached the lower end of the screw 64. Thisresult is achieved by the use of highslip type motors at 66,67, and theparticular manner by which they are interconnected, as described below.Hence the dual jack assembly 20 adapts itself to any spacing between thetankers manifold and the deck, within of course the limits of extensionof its legs.

The hydraulic motors 66,67 for the jacks 34,36 preferably are connectedin series in a hydraulic circuit diagrammatically illustrated in FIG.11, thus assuring that the travel of each leg 62 will be equal. Thishydraulic circuit comprises a conventional three-way valve 110 forstarting and stopping the motors and controlling the direction of flowof hydraulic fluid under pressure through them, and a pair of needlevalves or other variable orifice devices 112,114, each of which isconnected in parallel with the inlet and outlet ports of its respectivemotor, to regulate the quantity of flow through the motors for balancingtheir operation.

The motors 66,67 are of the high-slip type, so that if the tankers deck,etc., is uneven the motor of the first leg to contact the deck willstall and pass enough fluid to facilitate continued operation of theother motor until the second leg also comes to rest against the deck.Furthermore, during retraction of legs that have become out of phase,for example as above where one leg reaches the deck before the other,the motor which first stalls when its leg reaches its upper limit oftravel, i.e., when its stop 100 and stop element 102 come into contact,will allow sufficient passage of fluid to the other motor so that theother leg also can be fully retracted. This feature is especiallyimportant where the deck or other supporting surface beneath one of thejacks is not spaced from the tankers manifold the same as that beneaththe other jack.

The motors 66,67 are operated with hydraulic pressure preferablysufficient to assure that the jacks provide a small upward force on theloading arms coupling assembly 220 before the motor stall. When thevalve 110 is closed, the jacks will then remain in position to supportthe weight of the coupling and the loading arm, and transfer this weightin a balanced manner to the deck or other structure with which the feet68 are in contact.

Although the best mode contemplated for carrying out the presentinvention has been herein shown and described, it will be apparent thatmodification and variation may be made without departing from what isregarded to be the subject matter of the invention.

I claim:

I. A marine loading arm including a fluid-conducting boom sectionadapted for coupling to a manifold flange of a marine tanker, and a jackassembly mounted on the boom section for supporting the loading arm onthe tanker, said jack assembly comprising:

a. a pair of screw jacks, each jack having a housing,

a leg extensible from and retractile into said housing, and a helicalscrew for extending and retracting said leg with respect to saidhousing;

b. power means for rotating the helical screws;

c. first means for securing the jacks to each other in spaced, generallyparallel relationship; and

d. second securing means cooperating with the first securing means tomount the jack assembly on the loading arm.

2. A marine loading arm according to claim 1 wherein the power meanscomprises a pair of hydraulic motors, one secured to the housing of eachjack, and means interconnecting each motor with the helical screw of itsrespective jack.

3. A marine loading arm according to claim 2 wherein the interconnectingmeans of each jack comprises a motor shaft rotatable with respect to thejack housing, and a screw shaft non-rotatably secured to the motor shaftand the helical screw.

4. A marine loading arm according to claim 1 wherein the first securingmeans comprises a rigid beam member fixed at each end to the jackhousings, and a saddle member fixed to the beam member in an upwardlyoriented manner when the assembly is positioned in its functionalorientation.

5. A marine loading arm according to claim 4 wherein the second securingmeans comprises an elongated strap removably securable at each end tothe jack housings, the strap cooperating with the saddle member toremovably secure the assembly to the loading arm.

6. A marine loading arm according to claim 1 wherein each extensible leghas an inner and an outer end, a drive nut threaded about thescrew-shaft and fixed to the inner end of the leg, and a foot memberpivotally connected to the legs outer end.

7. A marine loading arm according to claim 6 including anti-rotationguide means extending between each jack housing and its extensible leg,whereby when the screw is rotated with respect to its housing theextensible leg is prevented from rotating.

8. A marine loading arm according to claim 7 including stop means on thescrew shaft cooperating with stop means on the drive nut to precludeover-extension and over-retraction of the leg with respect to thehousing.

9. A dual jack assembly adapted for supporting the outboard end of amarine loading arm, comprising:

a. a pair of screw jacks, each jack having a housing,

a leg extensible from and retractile into said housing, and a helicalscrew for extending and retracting said leg with respect to saidhousing;

b. power means for rotating the helical screws, said power meanscomprising a pair of hydraulic motors, one secured to the housing ofeach jack, and means interconnecting each motor with the helical screwof its respective jack, said motors being connected in series into asource of pressurized hydraulic fluid, said power means furthercomprising a variable orifice flow control means connected across thefluid inlet and outlet of each motor;

c. first means for securing the jacks to each other in spaced, generallyparallel relationship; and

d. second securing means cooperating with the first securing means tomount the jack assembly on the loading arm.

10. A dual jack assembly according to claim 9 wherein the motors are ofthe high-slip type facilitating continued but slow rotation of one motorafter rotation of the other motor has terminated.

UNITED STATES PATENT OFFICE QER'HFEATE OF CORRECTIQN PATmr NO. 3,799,197

DATED March 26,1974

iNVENTORt'S) HAROLD M. GIBBONS it is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below: 6

Column 3 lines 42-43 change "move-ment" to moment Signed and gals this 9fifth of August 1975 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN AINSII'MR ffifl ('nmmixsr'unvr uj'lulcnrsand Trulz'murkx

1. A marine loading arm including a fluid-conducting boom sectionadapted for coupling to a manifold flange of a marine tanker, and a jackassembly mounted on the boom section for supporting the loading arm onthe tanker, said jack assembly comprising: a. a pair of screw jacks,each jack having a housing, a leg extensible from and retractile intosaid housing, and a helical screw for extending and retracting said legwith respect to said housing; b. power means for rotating the helicalscrews; c. first means for securing the jacks to each other in spaced,generally parallel relationship; and d. second securing meanscooperating with the first securing means to mount the jack assembly onthe loading arm.
 2. A marine loading arm according to claim 1 whereinthe power means comprises a pair of hydraulic motors, one secured to thehousing of each jack, and means interconnecting each motor with thehelical screw of its respective jack.
 3. A marine loading arm accordingto claim 2 wherein the interconnecting means of each jack comprises amotor shaft rotatable with respect to the jack housing, and a screwshaft non-rotatably secured to the motor shaft and the helical screw. 4.A marine loading arm according to claim 1 wherein the first securingmeans comprises a rigid beam member fixed at each end to the jackhousings, and a saddle member fixed to the beam member in an upwardlyoriented manner when the assembly is positioned in its functionalorientation.
 5. A marine loading arm according to claim 4 wherein thesecond securing means comprises an elongated strap removably securableat each end to the jack housings, the strap cooperating with the saddlemember to removably secure the assembly to the loading arm.
 6. A marineloading arm according to claim 1 wherein each extensible leg has aninner and an outer end, a drive nut threaded about the screw shaft andfixed to the inner end of the leg, and a foot member pivotally connectedTo the leg''s outer end.
 7. A marine loading arm according to claim 6including anti-rotation guide means extending between each jack housingand its extensible leg, whereby when the screw is rotated with respectto its housing the extensible leg is prevented from rotating.
 8. Amarine loading arm according to claim 7 including stop means on thescrew shaft cooperating with stop means on the drive nut to precludeover-extension and over-retraction of the leg with respect to thehousing.
 9. A dual jack assembly adapted for supporting the outboard endof a marine loading arm, comprising: a. a pair of screw jacks, each jackhaving a housing, a leg extensible from and retractile into saidhousing, and a helical screw for extending and retracting said leg withrespect to said housing; b. power means for rotating the helical screws,said power means comprising a pair of hydraulic motors, one secured tothe housing of each jack, and means interconnecting each motor with thehelical screw of its respective jack, said motors being connected inseries into a source of pressurized hydraulic fluid, said power meansfurther comprising a variable orifice flow control means connectedacross the fluid inlet and outlet of each motor; c. first means forsecuring the jacks to each other in spaced, generally parallelrelationship; and d. second securing means cooperating with the firstsecuring means to mount the jack assembly on the loading arm.
 10. A dualjack assembly according to claim 9 wherein the motors are of thehigh-slip type facilitating continued but slow rotation of one motorafter rotation of the other motor has terminated.